Olympus E-M5 has a Micro Four Thirds lens mount and currently there are 92 native lenses available for this mount.
E-M5 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on E-M5.
Since Olympus E-M5 has a Four Thirds sensor, it has a focal length multiplier of 2x so you have to multiply lenses original focal length with this multiplier to find the Full Frame equivalent focal length of the lens when mounted on E-M5.
You may also also be interested in these:
Olympus E-M5 Lenses with Image Stabilization
Olympus E-M5 Lenses with Weather Sealings